Figure 5. miR-638 represses CRC cell growth, invasion and cell cycle progression by downregulating TSPAN1 expression.

(A) TSPAN1 protein expression was determined in CRC cells using Western blotting. (B) The knockdown of TSPAN1 by siRNA significantly repressed CRC cell proliferation, and upregulation of miR-638 did not suppress cell growth in TSPAN1-depleted HCT-116 or LoVo cells. miR-638 silencing promoted cell growth, but did not promote cell proliferation in TSPAN1-depleted CRC cells. (C) The upregulation of TSPAN1 (ORF without 3′UTR) markedly promoted cell growth and abrogated miR-638-induced cell growth inhibition in HCT-116 or LoVo cells. (D) Cell cycle analyses were performed in LoVo and HCT-116 cells transfected with miR-638, TSPAN1 or vector control (*p < 0.05; **p < 0.01; ***p < 0.001; NS, not significant). (E) Upregulation of the TSPAN1 promoted cell invasion and abrogated miR-638 induced invasion-inhibition in CRC cells (*p < 0.05; **p < 0.01).